The invention concerns an adaptable sensor for a dashpot for measuring the difference between the speed of the body of a motor vehicle and that of its axle. The dashpot is usually the link that more or less transmits vibrations transmitted from the roadway by the suspension system to the body. Variable hydraulic dashpots are usually employed for this purpose.
To comply with the demands of the automotive industry for increased safety and comfort it is becoming increasing necessary to measure the speed of the body of a vehicle in relation to that of its axle. The results must be precise enough to be utilized to control or set the dashpot. The speed-difference signal can accordingly be considered a profile of the roadway that the vehicle is traveling over.
The as yet unpublished German 3 909 190 discloses a dashpot sensor for a semiactive vehicle body controlled with a speed-difference sensor. Without complex and expensive sensors, the speed difference is measured with a stationary permanent magnet and a sensor coil that travels over it. When a vibration occurs, the magnetic flux induces a voltage in the traveling coil that is proportional to the difference between the speed of the body and that of the axle.
German GM 8 524 086 also discloses a sensor, which comprises a moving permanent magnet and stationary coils.
German OS 2 303 104 discloses an acceleration sensor with a spring that moves a coil through a magnetic field.
German OS 3 538 349 discloses a device equipped with a very wide range of different kinds of sensor.
German OD 3 522 010 discloses a distance sensor with a coil and a core that moves in relation to it.
Finally, German OS 3 536 201 describes an instrument for detecting the relative positions of two moving components with the object of obtaining a reliable signal at both the top and the bottom.
All known sensors or systems are permanently integrated into or onto the dashpot. This is a serious drawback in that sensors cannot be mounted on existing dashpots or resilient wheel-guided legs. Furthermore, the coils or other components often demand electricity. Finally, at the current state of the art, with either the magnet or the coil always stationary, the difference signal is obtained from the relative motion between the coil and the magnet.